WULPUS PRO

A base platform for wearable ultra-low-power ultrasound

Independent fork by @Sergio5714 (Sergei Vostrikov)

WULPUS PRO module with PolyCMUT transducer.

Introduction

This repository contains the work in progress on the WULPUS PRO ultrasound platform, a successor of the WULPUS Project. It features +30V unipolar programmable pulser, time-multiplexed multichannel acquisition frontend with TGC, optonal envelope extractor and support of PZTs and CMUTs. The module is compact (40 x 20 mm footprint) and lightweight (5g), allowing integration with external host PCB.

System diagram

WULPUS PRO system diagram

Hardware photos

WULPUS PRO evaluation board
Top view	Bottom view

Specifications

WULPUS PRO builds on the original WULPUS platform and keeps the same low-power wearable ultrasound philosophy while extending the hardware and communication options. The table below compares the main features of WULPUS PRO with those of the original WULPUS platform.

Feature	WULPUS	WULPUS PRO
Number of channels	8, time-multiplexed	16, time-multiplexed
Supported transducers	PZT transducers	PZT transducers, CMUTs
Excitation amplitude	15 V unipolar	30 V unipolar
Excitation frequency	~100 kHz to 4 MHz	~100 kHz to 10 MHz
Transducer biasing	-	Indirect or direct bias, -30 V or 30 V
Analog front-end	10 dB LNA + 30.8 dB PGA	6 dB LNA + 70 dB VGA
TGC support	No (fixed gain)	Yes (linear profile)
Maximum PRF	50 Hz	300 Hz
Power budget at 50 Hz PRF	<=25 mW	<=40 mW
Wireless link	BLE	BLE or Wi-Fi (via host)
Form factor	46 x 25 mm footprint	40 x 20 mm footprint

Full WULPUS PRO specifications are available in docs/full_specifications.md.

Structure of the repository

This repository has the following folders:

• hw, containing the CAD source files for:
  • WULPUS PRO acquisition PCB, located at hw/wulpus_pro_acq_pcb_dev_board
  • optional WULPUS adapter PCB for polyCMUT transducers, located at hw/wulpus_polycmut_adapter; this board was developed for research purposes
• fw, containing the firmware source code, namely:
  • MSP430 ultrasound MCU firmware required for the WULPUS PRO module, located at fw/msp430
  • ESP32 Wi-Fi firmware for the Seeed Studio XIAO ESP32-C6, located at fw/esp32
  • nRF52 firmware, located at fw/nrf52:
    • nRF52832 DK board firmware, located at fw/nrf52/ble_peripheral/US_probe_nRF52_firmware
    • nRF52840 USB dongle firmware, located at fw/nrf52/peripheral/US_probe_dongle_firmware
• sw, containing the Python code for the WULPUS PRO API and graphical user interface
• docs, containing project-level documentation such as the full WULPUS PRO specifications

Documentation

WULPUS PRO builds on top of the original WULPUS platform. Please refer to the original WULPUS User Manual for assembly instructions, example measurements, and GUI overview.

For WULPUS PRO-specific documentation, see:

• Full specifications
• Hardware README
• MSP430 firmware README
• ESP32 Wi-Fi firmware README
• nRF52 BLE firmware README
• Software README

Build Instructions

To build your own instance of the WULPUS PRO platform, complete the following steps:

1. PCB manufacturing and assembly
   Use the design files, schematics, and bills of materials under the hw folder. The WULPUS PRO acquisition PCB is required. The polyCMUT adapter PCB is optional and intended for research setups using polyCMUT transducers.

2. Flash the required MSP430 firmware
   The MSP430 ultrasound MCU firmware is required for the WULPUS PRO module. Follow the instructions in fw/msp430 to set up the toolchain, compile the firmware, and flash the MSP430 MCU.

3. Prepare a host system
   Choose one of the supported host interfaces:

   • ESP32-based Wi-Fi host, for example the Seeed Studio XIAO ESP32-C6. Follow the instructions in fw/esp32/README.md to build and flash the ESP32 firmware. After flashing, complete the provisioning step so WULPUS PRO can connect to your Wi-Fi network.
   • nRF52 BLE host, using the nRF52832 DK board and nRF52840 USB dongle. This is the legacy BLE setup. Follow the instructions in fw/nrf52/README.md to compile and flash both firmwares.

4. Python dependencies installation on the host PC
   Follow the instructions in sw to install the Python dependencies. With uv, the basic setup is:

   uv sync
   uv run jupyter notebook

PCBWay shared projects for WULPUS PCBs

For convenient one-click PCB production and assembly, you can use the PCBWay shared projects (optional; DIY via the hw folder is also supported):

• WULPUS PRO Evaluation Board v1.0.0

This option is convenient for outsourced PCB production and assembly, with an estimated ~1 month lead time and a price of about USD 220 per probe (evaluation board), based on mid-2026 pricing.

Usage

Wi-Fi setup with XIAO ESP32-C6

1. Connect the ESP32 host module to the WULPUS PRO board using the pin mapping documented in fw/esp32/README.md.

2. Power the ESP32-based host module, for example the Seeed Studio XIAO ESP32-C6 running the firmware from fw/esp32.

3. Power the WULPUS PRO board through the connector or debug pin headers.

4. Start Jupyter from the sw folder:

   uv run jupyter notebook

5. Open wulpus_pro_wifi_example.ipynb in the browser and follow the notebook instructions for discovery, connection setup, configuration transfer, and acquisition.

BLE setup with nRF52 (legacy)

1. Connect the nRF52 DK to the WULPUS PRO board using the pin mapping documented in fw/nrf52/README.md.

2. Plug in the USB dongle and power the nRF52 DK via USB.

3. Check the dongle connection. The green LED should light up. If it does not, press the reset button on the nRF52 DK and try again.

4. After confirming dongle connectivity, power the WULPUS PRO board through the connector or debug pin headers.

5. Start Jupyter from the sw folder:

   uv run jupyter notebook

6. Open wulpus_pro_gui.ipynb in the browser and follow the notebook instructions to begin acquisition.

Citation

If you would like to cite this repository, please use:

@misc{wulpus_pro_repo_sergio5714_2026,
  title={WULPUS PRO: A Base Platform for Wearable Ultra-Low-Power Ultrasound (Independent Fork)},
  author={Vostrikov, Sergei and Villani, Federico and Hirschi, Cedric and Cossettini, Andrea and Benini, Luca},
  year={2026},
  howpublished={GitHub repository},
  url={https://github.com/Sergio5714/wulpus-pro}
}

Changelog

See CHANGELOG.md for release notes and main project changes.

Authors

This fork is maintained independently by @Sergio5714 (Sergei Vostrikov).

The WULPUS PRO system was originally developed at the Integrated Systems Laboratory (IIS) at ETH Zurich by:

• Sergei Vostrikov (PCB design, firmware, software, open-sourcing)
• Federico Villani (PCB design, component selection)
• Cedric Hirschi (firmware, software)
• Andrea Cossettini (supervision, project administration)
• Luca Benini (supervision, project administration)

Thanks to all the people who contributed to the WULPUS PRO platform:

• Sebastian Frey (design review)

License

The following files are released under Apache License 2.0 (Apache-2.0) (see sw/LICENSE):

• sw/

The following files are released under Solderpad v0.51 (SHL-0.51) (see hw/LICENSE):

• hw/

The fw/msp430/, fw/nrf52/, and fw/esp32/ directories contain third-party sources that come with their own licenses. See the respective folders and source files for the licenses used.

Limitation of Liability

In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall any Contributor be liable to You for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising as a result of this License or out of the use or inability to use the Work (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if such Contributor has been advised of the possibility of such damages.